Siege of Shouchun (197)

The Siege of Shouchun occurred in 197 AD when the forces of Cao Cao and other warlords loyal to the Han dynasty laid siege to Yuan Shu's stronghold of Shouchun after Yuan Shu proclaimed himself Emperor. The coalition succeeded in destroying Yuan Shu's power, although he continued to be a threat to China's unity until his death two years later.

Background
The warlord Yuan Shu set up his base at Nanyang in 189 AD, from which he made ambitious plans to become the ruler of all China as the Han dynasty was torn asunder by civil warfare. In 191 AD, the warlord Sun Jian pledged allegiance to Yuan Shu in exchange for aid against their shared rival Liu Biao, but Sun Jian was killed in battle with Liu Biao at the Battle of Xiangyang. His son and successor Sun Ce decided to enter Yuan Shu's service afterwards, and he gave the Imperial Seal to Yuan Shu in exchange for being given a regiment of troops with which he could conquer his family's ancestral home of Jiangdong in southeastern China in 193 AD. Yuan Shu's power grew as Sun Ce conquered several territories in Yuan Shu's name, and Yuan Shu attempted to expand his empire as an ally of Lu Bu, but he was defeated by Liu Bei and later by his former ally Lu Bu in 196. That same year, after Cao Cao took Emperor Xian of Han with him to Xuchang and became the new protector of the Imperial Court, Yuan Shu decided to use the Imperial Seal to proclaim himself Emperor of the "Zhong dynasty", intending on blocking Cao Cao's rise to power. In 197 AD, Cao Cao issued edicts to Sun Ce and Lu Bu and urged them to join his campaign against Yuan Shu, whom the Imperial Court had branded a traitor, and Liu Bei also joined the coalition.

Siege
Yuan Shu had his men ravage the Chenliu area to replenish his army's depleted supplies, but he and his 100,000 troops were soon encircled in Shouchun as Liu Bei and Lu Bu's forces arrived by land and Sun Ce's forces by sea. Sun Ce's forces attacked the western gate of Shouchun, with Sun Ce's sister Sun Shangxiang attacking the western garrison. There, the commander Lei Bo came to have doubts about Yuan Shu's legitimacy due to Sun Ce's rebellion against him. After his forces were routed and he was defeated, he decided to abandon Yuan Shu's cause. The besiegers then captured a ballista unit from Chen Lan and used them to annihilate the archers positioned on the city walls, clearing the way for the besiegers to advance into the city. The coalition forces then prepared a battering ram and used the ballistae to annihilate Yuan Shu's rock throwers, allowing for the ram to breach the walls. The coalition forces then rushed into the city and defeated the castle's commanders, including Liang Gang and Li Feng. Yuan Shu's officers went into hiding within the castle, forcing the coalition forces to search all of the corridors for them. Yue Jiu was located in the north, and he warned the coalition forces that Yuan Shu had already escaped. Chen Ji was then located in the south, and he was forced to fight as well. However, Yuan Shu's forces in the castle were overwhelmed and defeated. Not long after, Yuan Shu, Yuan Yin, Ji Ling, Zhang Xun, Chen Lan, Lei Bo, and a team of supply captains were caught retreating northwards with a large army, and the coalition forces set out in hot pursuit of them. Chen Lan and Lei Bo defected to the coalition forces as the force passed a garrison en route to the escape route, stalling Yuan Shu's escape. The coalition forces then decimated Yuan Shu's army, and Yuan Shu's influence was reduced to a minimum.

Aftermath
After the campaign against Yuan Shu was completed, Cao Cao became the most powerful warlord in China. Liu Bei launched a failed rebellion against Cao Cao in Xu Province, but Cao Cao's larger army scattered Liu Bei's forces and forced him to flee to the court of Yuan Shao. With Liu Bei defeated, Cao Cao looked north to battle against Yuan Shao for control of the Central Plains, meeting him at the Battle of Guandu.